If it sounds too good to be true, it normally is! Onion juice is a popular home remedy for hair loss online. And there is also some research to suggest it may be effective for specific types of hair loss. But could curing hair loss really be this simple? Let’s take a look at the evidence.
Why onion juice?
Onions: the strong-smelling, colorful vegetables that make you cry. Why would you ever want to put them on your hair?
Well, online advocates of onion juice for hair point to the high sulfur content of onions, arguing that this promotes healthy growth and prevents hair loss.
And there is a grain of truth to this claim.
Sulfur is important for the formation of keratin; the key structural component of hair. Without sulfur, hair may become brittle and weak. The theory goes that onion juice contains an easily absorbable form of sulfur, which helps form the key amino acids needed for keratin. However, it’s doubtful whether the body can make use of this sulfur when applied directly to the scalp in the form of onion juice.
Even so, there a medical trial of onion juice for hair loss found that regrowth was observed in 86.9% of patients.
But, as always, it’s not that simple. So don’t go rushing out to the grocery store to stock up on onions just yet.
Onion juice for alopecia areata
The study in question tested whether onion juice could be used to regrow hair in patients with alopecia areata.
Alopecia areata is an autoimmune disorder where hair is lost in circular patches in seemingly random areas of the scalp. Onion juice was applied directly to the scalps of patients with alopecia areata, and caused some pretty impressive hair regrowth:
“Re-growth of terminal coarse hairs started after two weeks of treatment with crude onion juice. At four weeks, hair re-growth was seen in 17 patients (73.9%), and, at six weeks, the hair re-growth was observed in 20 patients (86.9%) and was significantly higher among males (93.7%) compared to females (71.4%) P<0.0001. In the tap-water treated-control group, hair re-growth was apparent in only 2 patients (13%) at 8 weeks of treatment with no sex difference. The present study showed that the use of crude onion juice gave significantly higher results with regard to hair re-growth than did tap water (P<0.0001), and that it can be an effective topical therapy for patchy alopecia areata.”
But alopecia areata is rare. The vast majority of hair loss – for both men and women – is due to androgenetic alopecia, otherwise known as pattern hair loss.
Whereas alopecia areata occurs in just 0.1% of the population, pattern hair loss affects roughly 70% of men and 40% of women at some point in their lives.
Pattern hair loss is typically characterised by hair loss from the top of the scalp, but not the back and sides. In men, this usually starts with a receding hair line or thinning in the crown area. Mens hair loss is measured by the Norwood scale.
In women, hair is lost from the top of the scalp in a slightly different pattern. Whereas men tend to go bald in particular areas, female pattern hair loss is characterised by a general thinning on top of the scalp. This progression is measured by the Ludwig scale.
But alopecia areata and androgenetic alopecia appear to have completely different causes. Alopecia areata is an autoimmune disorder, where the body’s immune system attacks the hair follicles. Androgenetic alopecia is believed to be caused by hormones.
So even if onion juice is effective for alopecia areata, this doesn’t necessarily translate to an effective treatment for the majority of hair loss sufferers. Nevertheless, it is commonly recommended online – so is there something to it?
Onion juice and DHT
Ask your doctor and he’ll tell you that pattern hair loss in men is caused by dihydrotestosterone (DHT); a by-product of testosterone. Despite the myths, it is not necessarily true that bald men have more testosterone – only that their hair follicles are more sensitive to DHT.
In women, the causes of pattern hair loss are less well understood, though hormones are thought to play a role as well.
DHT is said to bind to receptors in hair follicles, causing them to get smaller and smaller until hair is no longer visible.
But there is no evidence that onion juice has any effect on DHT levels in the scalp.
Of course, this doesn’t prove it has no effect – only that it hasn’t been tested yet. But I wouldn’t hold my breath waiting for such tests to be conducted. There’s just not much reason to expect onion juice to have any effect on scalp DHT levels.
However, let’s not discount onion juice just yet! A growing body of evidence is suggesting that DHT is not the real cause of pattern hair loss. For example, DHT is known to cause hair to grow everywhere else in the body. Not only that, nobody has ever conclusively established that DHT directly causes hair loss. So far, all we know is that reducing DHT generally slows hair loss – but this may be a side effect of something else.
So even if onion juice has no effect on scalp DHT, it may yet prove to be an effective hair loss treatment.
Onion juice and inflammation
Inflammation is the body’s response to foreign organisms, such as viruses or bacteria.
Normally, this is a good thing. White blood cells rush to the area and neutralize these foreign organisms. But sometimes this inflammatory response occurs when it isn’t necessary.
Interestingly, this is what’s behind alopecia areata. The immune system mistakes the hair follicles for foreign invaders and attacks them, destroying the hair.
But inflammation usually accompanies pattern baldness too – though not in quite the same way.
Often, men and women with pattern hair loss find their scalp to be itchy in the area of hair loss. This is due to inflammation. Many speculate that inflammation is the real cause of hair loss.
Some shampoos for hair loss reduce bacteria in the scalp. This reduces the inflammation and also the immune response. Perhaps unsurprisingly, these shampoos have also been demonstrated to reduce hair loss.
And some studies suggest onions may have similar anti-inflammatory properties. If true, this may explain why onion juice was able to reverse alopecia areata in the study mentioned earlier. And since inflammation is also linked to pattern hair loss, onion juice may be effective for this condition too.
Onion juice for hair loss: is it worth it?
There is evidence to suggest topical onion juice may be beneficial for certain types of hair loss – namely, alopecia areata. And some of these benefits may possibly transfer to pattern hair loss too.
But onion juice is not a miracle hair loss cure.
The evidence just isn’t strong enough to suggest it will have any major impact on pattern hair loss – male or female. Reducing inflammation will definitely help, but it’s highly unlikely that by itself onion juice will reduce it enough to regrow or maintain hair. There are also far more effective (and better smelling!) ways to reduce inflammation in the scalp and throughout the body.
Consider this: onions have been a popular folk medicine for thousands of years. If they really cured hair loss, nobody would be bald!
Let’s not dismiss these pungent vegetables completely, though.
Traditionally, pattern hair loss has been explained as a purely genetic condition. But modern research is beginning to reveal the importance of environmental factors.
One of the most important environmental factors is diet. Onions – especially raw ones – are rich in antioxidants and important nutrients like biotin, which may help control blood sugar and prevent inflammation. There’s even evidence to suggest eating onions can increase testosterone levels.
But let’s not get carried away.
Onions, whether you eat them or rub them directly into the scalp, are not a miracle hair loss cure. Despite the impressive 87% hair regrowth statistic from the alopecia areata study, these results are not likely to be representative for all types of hair loss.
How to prepare onion juice for hair loss
It’s fair to say the evidence supporting onion juice for hair loss is far from conclusive. But if you’re still tempted to give it a try, here’s what you’ll need:
Chop your onion into smaller pieces, add it to the blender along with your oil, and blend into a paste. You may need to use a fine sieve if you have unblended pieces of onion left over!
Apply your onion juice directly to the scalp and leave to soak for around an hour. If you do decide to try this out, I’d definitely recommend combining it with scalp massage. Don’t forget to wash your hair thoroughly afterwards to get rid of the smell!
But be warned: some reports online have complained that onion juice can cause a red or itchy scalp.